It is important to remember that our events are drug tested. If you take ANY medication for any reason, you must verify if it if your medication is permitted or prohibited. If prohibited, a TUE (Therapeutic Use Exemption) application must be submitted. The National Office can help through that process if needed.
Additionally, many pre-workouts contain prohibited substances, whether declared on the ingredient labels or a hidden (contaminated) substance within the product. You as the athlete are responsible for what you put in your body and may cause a failure, which happened a few years ago at the Arnold. Consumer beware and only use products that are third party tested to help protect yourself.